The present invention relates to a pulley belt installer for hanging a pulley belt between a pair of pulleys in a belt type stepless transmission having a pair of pulleys with variable groove widths and a pulley belt that is hung therebetween.
The belt type stepless transmission serving to transmit motive power, such as in a vehicle, generally has, as shown in FIG. 10, a pair of pulleys, each having a V-groove with a variable width, and a pulley belt that is hung around the pulleys so as to link them, wherein by increasing and decreasing the widths of a drive-side primary pulley PM and a driven-side secondary pulley SD oppositely, the effective radii of the pulleys are continuously varied so as to achieve a stepless change in speed. In the belt-type stepless transmission shown in FIG. 10, the opposing outer-facing halves of the pair of pulleys are in the condition of a maximum speed reduction ratio, and the inner-facing halves thereof are in the condition of a minimum speed reduction ratio.
In assembling this stepless transmission, before assembling the primary pulley PM and the secondary pulley SD into a housing of the stepless transmission, it is necessary to hang a pulley belt PB between the pulley PM and the pulley SD, and because the length of the pulley belt PB is established as relatively short in the relation between the outer diameters of the pulleys PM and SD, it is difficult to install the pulley belt with both the pulleys positioning vertically. Because of this problem, a known pulley installer for installing the pulleys was disclosed in Japanese Patent No. 2681595, which is shown in FIG. 12A and FIG. 12B.
In this pulley installer of the past, as shown in FIG. 12A, a vacuum pump (not shown) is first used to develop negative pressure in a hydraulic chamber 19 of a primary pulley PM, so as to move a movable flange forming one wall part of a V-groove downward so as repel the spring force of a spring SP, thereby widening the groove of the primary pulley PM. Next, when a handle H is pulled up to an intermediate position, a roller R1 on an end part of an arm AM extending via a pivoting shaft 20 of the handle H moves downward, in response to which the primary pulley PM which had been supported by the roller R1 via an elevator stage 21 is also lowered. Then, as shown in FIG. 12B, when the handle H is pulled up further, another roller R2 provided on the handle H rises along an inclined surface of a cam plate CB mounted to a shift stage 22 as it presses against the cam plate CB, so as to push a secondary pulley SD upward at an inclination, via the shift stage 22, resulting in the secondary pulley SD to move upward at a prescribed angle, while maintaining its mutual parallelness with respect to the center of the primary pulley PM. As a result, fixed flanges of the primary pulley PM and the secondary pulley SD are pulled toward the V-groove of the other pulley, thereby reducing the shaft-to-shaft distance between the pulleys, in which condition a pulley belt PB is fitted into the V-grooves of the pulleys.
In the above-noted pulley belt installer, however, in order to shorten the shaft-to-shaft distance between the pulleys PM and SD, when installing the pulley belt PB, the pulleys PM and SD are moved so that the V-grooves overlap, and there is a chance that a pulley flange collides with the surface of a V-groove, when the V-grooves overlap, thereby resulting in damage. Because this surface of each V-groove is used as a sliding surface when the stepless transmission is operated, if the surface become damaged, there may be caused a damage to the pulley belt.
Accordingly, in view of the above-described problems with the related art, it is an object of the present invention to provide a more advantageous pulley belt installer for a belt-type stepless transmission.
An aspect of the present invention to achieve the object is a pulley belt installer for a belt-type stepless transmission including a first pulley having an expandable first groove, a second pulley having an expandable second groove, and a pulley belt for the first and second pulleys to be linked therewith, the pulley belt installer being operative to install the pulley belt around the first and second pulleys, wherein the pulley belt installer comprises a first holder configured to hold the first pulley, a first expander configured to expand the first groove, a second holder configured to hold the pulley belt with a first part thereof located in the first groove, and a rotator configured to rotate the second pulley with the second groove with a second part of the pulley belt located therein, at least at 90 degrees about a rotation axis crossing a center axis of the second pulley, into a position in which the center axis of the second pulley is paralleled to a center axis of the first pulley.
According to this aspect of the present invention, the first holder (serving as a pulley holder) holds one of a pair of pulleys (as the first pulley), the first expander (serving as a held pulley""s width expander) expands a groove width of a groove (the first groove) of the held pulley, thereby reducing its pitch circle diameter, the second holder (serving as a pulley belt holder) holds a pulley belt in a condition in which a part (the first part) of the pulley belt is located in the groove of the pulley held by the pulley holder, and the rotator (serving as a pulley rotator or swinger) rotates the other of the pair of pulleys (as the second pulley) in a condition in which another part (the second part) of the held pulley belt is located in a groove (the second groove) of the other pulley, at least 90 degrees about a rotation axis crossing a center axis of the other pulley, into a position in which the center axis of the other pulley is paralleled to a center axis of the held pulley. As the center axes are paralleled to each other by the above action, the pulley belt is installed between the pair of pulleys.
According to the pulley belt installer for a belt-type stepless transmission according to the present invention, therefore, because it is possible to install a pulley belt with causing the grooves of both pulleys to mutually overlap, it is possible to prevent damages to the pulley belt that otherwise might have been caused by damages to surfaces of the grooves of the pulleys, thereby improving the quality of the stepless transmission. Another effect of this installer is that, by automatically assembling the pulley belt, there is a reduction in the assembly steps.